Unitary overpressure vent panel structure

ABSTRACT

Unitary one-piece frameless overpressure vent panel assembly ( 10 ) includes a rigid, generally planar primary support member having a central relief opening ( 26 ), a rigid, generally planar secondary support member ( 44 ) provided with a central relief aperture ( 46 ), and a frangible vent panel ( 30 ) between the support members in full closing relationship to the relief opening and the aperture. A sealant element ( 48 ) may be provided between the vent panel and at least one of the support members in circumscribing relationship to the relief opening or aperture. At least one line of weakness ( 34 ) may be provided in the vent panel. A flexible gasket ( 58 ) secured to the secondary support member assures a fluid tight seal between the vent panel assembly and the structure defining a protected zone. Alternatively, a knife blade or the like may be provided adjacent the vent panel to effect severing thereof under a predetermined overpressure in lieu of a line of weakness in the panel.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to a unitary, one-piece, integrated,non-fragmenting overpressure vent panel assembly that may be installedin covering relationship to the pressure relief area of a combined zoneto be protected from the buildup of uncontrolled overpressures, and tothen be removed as a unit for replacement with a similar vent panelassembly after actuation thereof. The vent panel assembly is especiallyuseful for instantaneously venting dangerously high internal pressureswhich result from an explosion in a manner to preclude catastrophicbuildup of pressures within a confined area that is normally exposed torelatively low operating pressures. The vent panel assembly has utilityfor use in protecting equipment such as bag house dust collectors,cyclones, conveyors, bucket elevators, dryers, vacuum receivers,electrostatic precipitators, silos, storage bins, large pipes, andducting.

[0003] 2. Description of the Prior Art

[0004] Burst membranes or panels have been used for many years toprovide protection against explosions producing unpredictabledangerously high internal pressures which not only would be destructiveto the zone requiring protection, but also to surrounding equipment,processes and personnel. The burst panels are fabricated to rupture at apredetermined overpressure in order to vent the protected zone andprevent the buildup of pressures therein which in the case of anexplosion could completely destroy the structure defining the protectedzone.

[0005] Deployment of explosion vents has significantly increased inrecent years because of the promulgation of ever more strict governmentregulations regarding the level of permissible particulates emissionsthat may be discharged into the atmosphere. The mandated adoption ofdust collectors has correspondingly increased the risk of explosioninherent in the provision of such dust collecting equipment. The rise inthe number of explosions attributable to particulates explosion has madeit incumbent upon industry to provide effective means for adequatelycontrolling the explosion problem.

[0006] The need for explosion protection with improved dust collectionequipment is exacerbated by the fact that the dust collectors tend to beless rigidly constructed and not as able to withstand internalexplosions than was once the case. As a result, vent panels for ventingthe interior of dust collection apparatus must reliably rupture at arelatively low pressure in order to adequately vent the confined area tobe protected before excessive pressure has built up within that area.

[0007] Examples of explosion vent devices that have been previouslyproposed include the vent panels and burst membranes illustrated anddescribed in the assignee hereof U.S. Pat. Nos. 4,067,154, 4,662,126,4,777,974, 4,821,909 and 6,070,365. Although these vent units have beenfound to be satisfactory for protection of a variety of dust collectionapplications where there is exposure to an unpredictable catastrophicexplosive event, the prior vent panel devices have involved amultiplicity of parts which must be assembled in place over the ventopening of the confined zone to be protected, and to then bedisassembled piece by piece upon venting of the burst panel of theexplosion vent for replacement of the burst panel.

[0008] Typically, the operator of the dust collecting equipment has beenresponsible for providing suitable frame structure for receiving a burstpanel with the supplier of the panel furnishing a burst membrane whichcomplies with the dimensional specifications of the user's mounted inplace frame structure. In the case of an initial installation, it is notuncommon for the burst panel supplier to provide the user withdimensional specifications for fabrication of frame structure requiredto mount a burst panel of standard configuration and dimensionsestablished by the supplier. The burst panel is then mounted in place onthe structure to be protected using hardware and fasteners supplied bythe user.

[0009] Upon actuation of a burst panel by an overpressure condition inthe structure to be protected, the actuated burst panel had to beremoved from the structure defining a confined zone part by part,usually involving a number of steps and disconnection of a series offasteners such as bolts and the like. Replacement of the panel requiredthe same number of operations and steps to refit another burst panelover the pressure relief opening in the dust collecting structure.

SUMMARY OF THE INVENTION

[0010] It is a primary object of this invention to provide a unitary,integrated, one-piece overpressure vent panel assembly which may beinstalled over and removed as a unit from a pressure relief area of aconfined zone to be protected from buildup of uncontrolledoverpressures.

[0011] In a preferred embodiment, the unitary vent panel assemblyincludes a rigid, generally planar primary support member having acentral pressure relief opening, a frangible vent panel carried by theprimary support member in full closing relationship to the reliefopening, a rigid, generally planar secondary support member overlyingthe vent panel and having a central relief aperture, and structureinterconnecting the primary support member, the vent panel and thesecondary support member to provide a rigid, integrated, one-pieceoverpressure vent panel assembly. In one form of the invention, thefrangible vent panel is provided with a line of weakness defining anon-fragmenting burst pattern of the panel when the panel is subjectedto an overpressure of predetermined magnitude.

[0012] The structure interconnecting the primary support member, thevent panel and the secondary support member may take any one of a numberof forms including for example, a series of spaced rivets extendingthrough the support members and the vent panel and positioned around theperimeter of the relief opening and the primary support member and theaperture in the secondary support member. Alternatively, the peripheryof the panel may be laser welded to either the primary support member orthe secondary support member or both. In instances of relatively lowtemperature applications, an adhesive layer may be used to affix thepanel to one or both of the support members.

[0013] A fluid tight seal should be provided between the panel and oneor both of the support members in full surrounding relationship to therelief opening in the primary support member and the aperture in thesecondary support member. A sealant element preferably ofcross-sectional tubular configuration and containing a gaseous fluid maybe provided between the panel and at least one of the support memberswhich extends around the full perimeter of the relief opening and theaperture in respective support members. A planar spacer member in theform of an apertured plate is provided in association with the sealantelement between the panel and a corresponding support member to preventundue compression of the sealant element and thereby maintain theintegrity of the seal over extended periods of time. As a result of theprovision of the spacer member, a constant space is maintained betweenthe rupture panel and the opposed secondary support member resulting inthe sealant element always being compressed to the same degreeregardless of the force applied in initial assembly of the vent panelassembly, or during in field work on the assembly. The sealant elementalways substantially returns to its original state because of itselastic memory when it is necessary to replace an actuated vent panel.

[0014] In cases where the panel is welded to one of the support membersaround the periphery of the panel or a substantially non-compressibleadhesive is used to join the primary support member to the secondarysupport member, the spacer plate normally provided in surroundingrelationship to a sealant element may be omitted.

[0015] The overall configuration of the unitary overpressure vent panelassembly hereof may be of quadrate overall shape, either rectangular orsquare, or may be of circular configuration. The relief opening in theprimary support member and the aperture in the secondary support membergenerally will be of a shape complemental with the overall shape of theassembly.

[0016] The panel may be fabricated of various materials and thicknessesdepending on the burst pressure required for a specific use. Typically,the panel is of a corrosion resistant material such as stainless steelor exotic alloys with the configuration of the score pattern and thedepth of the score cooperating to assure opening of the panel to meet anoverpressure specification.

[0017] Although the rigid, integrated, one-piece overpressure vent panelassembly of this invention has primary and advantageous utility forprotecting confined areas from uncontrolled explosions within theinterior of the area, the one-piece assembly may also be used forrelatively low pressure applications in which it is desirable ornecessary to vent an area whenever a predetermined overpressurecondition less than that occurring where an explosion hazard exists. Inaddition, in those applications where the required protective burstpressure is so low that full opening of the vent panel assembly may notbe readily obtainable, especially if the vent panel of the vent assemblyis not provided with burst pattern defining lines of weakness, one ormore sharp knives or the like may be associated with the panel foreffecting rupture thereof upon excursion of a relatively thin panel whena predetermined overpressure is applied to the vent.

[0018] The provision of a rigid, planar, spacer of predeterminedthickness in surrounding relationship to the sealant element is torqueindependent thus preventing too high or too low torque pressures beingapplied to the vent panel during fabrication thereof as a result ofovertightening or not applying sufficient tightening force to themounting bolts of the vent panel assembly. In addition, a sleeve may beprovided around each of the bolts securing the unitary vent panelassembly to the supporting structure of the confined area to preventapplication of excessive force to a gasket between the secondary supportmember of the unitary vent panel assembly and the support frame on thebag house, vessel or other area structure to be protected.

[0019] Burst pressure controlling slots in the vent panel are preferablydisposed in positions such that they are all located beneath the primarysupport member and communicate with the surrounding atmosphere and notthe confines of the structure to be protected. As a consequence, thevent panel is not subjected to higher temperatures that maybe presentwithin the processing vessel or other apparatus thus precluding the ventpanel from being adversely affected by elevated temperatureapplications. In addition, the vent panel cannot be touched, damaged ordeformed during handling or installation.

[0020] In an alternate form of the invention, especially useful forvacuum condition applications, the vent panel may be provided with anoutwardly projecting peripheral flange portion configured to meet withan integral, upstanding flange forming a part of the primary supportmember and surrounding the relief opening in the primary support member.A series of elongated relief tabs may be provided between the flange ofthe vent panel and the flange of the primary support member forcontrolling bursting of the panel under a predetermined overpressure.Each of the relief tabs has a pair of openings, with one of the openingsbeing joined by pin means or the like to the flange of the primarysupport member while the other opening of the relief tab is connected tothe flange of the vent panel. The burst pressure of the panel can becontrolled by varying the material of construction, the thickness, andthe width of the relief tab between respective openings therein. Sincethe relief tabs separate and permit the vent panel to be released onlywhen a tension force is applied to the tabs sufficient to permit rupturethereof, the vent panel is especially adapted for vacuum conditions inthat release tabs are subjected to a separation force only when anoverpressure occurs in a direction applying a tension force to therelease tabs.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a side elevational, generally schematic representationof a particulates collector such as a conventional bag house andillustrating a unitary overpressure vent panel assembly of thisinvention mounted on one of the sidewalls of the bag house;

[0022]FIG. 2 is a fragmentary enlarged plan view of the unitaryoverpressure vent panel assembly as depicted in FIG. 1, with parts beingbroken away for clarity;

[0023]FIG. 3 is a perspective exploded view of the vent of the unitaryoverpressure vent panel assembly with the mount therefore forming a partof the bag house also being illustrated;

[0024]FIG. 4 is an enlarged, fragmentary, vertical cross sectional viewtaken along the line 4-4 of FIG. 2 and looking in the direction of thearrow;

[0025]FIG. 4A is a vertical cross-sectional view along the same line asFIG. 4 and illustrating the preferred tubular sealant element betweenthe vent panel and the spacer plate;

[0026]FIG. 5 is an enlarged, fragmentary, vertical cross sectional viewtaken along the line 5-5 of FIG. 2 and looking in the direction of thearrows;

[0027]FIG. 6 is a plan view of an alternate embodiment of theoverpressure vent panel assembly illustrating another score lineconfiguration of the panel;

[0028]FIG. 7 is a plan view of a further embodiment of the overpressurevent panel assembly and showing an alternate score line configuration;

[0029]FIG. 8 is a plan view of another embodiment of the overpressurevent panel assembly and depicting a still further score lineconfiguration;

[0030]FIG. 9 is a plan view of a circular embodiment of the overpressurevent panel assembly; and

[0031]FIG. 10 is an enlarged fragmentary end view of an alternateembodiment of the overpressure vent panel assembly in which the ventpanel is of the multiple dome type with the dome section of the panelbeing shown in section for clarity.

[0032]FIG. 10A is a plan view of the overpressure vent panel assembly ofFIG. 10.

DETAILED DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

[0033] The principal, although not exclusive, utility for the rigid,integrated, one-piece overpressure vent panel assembly hereof is inexplosion protection applications. To that end, the unitary overpressurevent panel assembly 10 as shown in the drawings is illustrated inoperative position in a typical installation such as the upright sidewall 14 of a particulates collector in the nature of a bag house 12having an inlet 16 and an outlet 18. Bag house 12 conventionally isprovided with a plurality of filters which for example may be looselywoven fabric bags mounted over respective outlet conduits whichcommunicate with the interior of structure 12.

[0034] It is to be understood that mounting of unitary overpressure ventpanel assembly 10 on the side wall 14 of bag house 12 is forillustrative purposes only and the assembly 10 may be positioned in anyone of a number of strategically determined locations depending upon thetype of confined zone to be protected from an explosion, the location ofthe structure on which the overpressure vent panel assembly 10 is to bemounted, and avoidance of the explosive force through the open ventundesirably impinging on adjacent equipment.

[0035] The preferred overpressure vent panel assembly 10 as illustratedin FIGS. 1-5 is of overall quadrate configuration. Accordingly, the sidewall 14 of bag house 12 is provided with a rectangular opening 20. Avent panel mounting frame 22 is fixedly secured to side wall 14 insurrounding relationship to opening 20 through means such as a series ofbolts 24. It is to be understood in this respect that frame 22 may bewelded to the side wall 14 or otherwise permanently secured to the wallstructure.

[0036] Explosion vent panel assembly 10 includes a rigid, generallyplanar primary quadrate support member 26 having a central rectangularrelief opening 28. Member 26 preferably is of stainless steel, carbonsteel or exotic alloys, with an exemplary construction having athickness approximately 0.08″. It is to be observed from FIGS. 4 and 5that primary support member 26 has an integral peripheral lip 29 thatmay for example be about 0.4″ wide and which extends around the entireperimeter of the planar portion of member 26 for increasing the rigidityof the member 26. The width of each side of support member 26 betweenthe corresponding lip 29 and the inside edge of relief opening 28 mayfor example be about 1 ¾″. The overall area of relief opening 28 variesdepending upon the application of overpressure vent panel assembly 10and the area that must be vented in the event of an explosive eventwithin the confines of a protected area such as the internal volume ofbag house 12.

[0037] A vent panel 30 is mounted against the interface 32 of primarysupport member 26 within the quadrate margin defined by lip 29 as shownfor example in FIGS. 4 and 5. Panel 30 may be of varying materials,including for example, stainless steel or other exotic alloys.Generally, panel 30 is provided with a score line in one face thereofwhich in cooperation with the material from which panel 30 is fabricatedand the thickness of that material determines the overpressure at whichthe panel will burst and relieve the pressure buildup within theconfined area to be protected such as the interior of bag house 12. Inthe embodiment of the explosion vent panel assembly shown in FIGS. 1-5,the score pattern 34 shown for exemplary purposes only, includes anelongated central score line segment 38 connected to opposed V-shapedsegments 40 and 42 at opposite ends of line segment 38. The depth ofscore pattern 34 is a function of the burst pressure at which the ventpanel 10 must open and varies from job to job.

[0038] A rigid, generally planar secondary quadrate support member 44 ismounted within the confines of primary support member 26 adjacent theinterface 32 thereof and preferably is of stainless steel, carbon steelor an exotic alloy also having a thickness of about 0.08″ where theprimary support member 26 is fabricated of material of that thickness.Support member 44 has a central rectangular aperture 46 therein ofdimensions approximately equal to the dimensions of relief opening 28 inprimary support member 26. Each side of secondary support member 44 isof a width such that the outer perimeter thereof is approximately thesame dimensions as the outer dimensions of panel 30 as shown in FIGS. 4and 5.

[0039] A transversely tubular element 48 b of flexible sealant materialtrapping a quantity of a compressible fluid such as air is provided asshown in FIG. 4A between the inner face 50 of panel 30 and the opposedface 52 of secondary support member 44. An enlarged cross-sectional viewof element 48 b is illustrated in FIG. 11. Another exemplary tubular,flexible element 48, is shown in enlarged cross-section in FIG. 12. Anon-tubular, flexible sealant element 48 a as depicted in FIG. 13 andillustrated schematically in FIG. 4 may also be used for providing aseal between panel 30 and secondary support member 44. Sealant element48 b may either be of synthetic foam resin material, or a sufficientlyflexible solid polymer for use in this application. A rigid, generallyplanar, quadrate spacer plate 54 is provided between face 50 of panel 30and the opposing face 52 of secondary support member 44 in surroundingrelationship to the element 48. The thickness of plate 54 is chosen toassure that flexible element 48 is compressed only to a predeterminedextent to assure that an adequate seal is provided between the processside and the atmospheric side of the vent panel assembly 10 around theperimeter of the vent panel 30 under the normal operating conditionswithin the protected confined area likely to be encountered for thatspecific application. The flexible sealant element 48 may be constructedof various materials including silicone, Teflon, EPDM, Viton, and otherequivalent compounds. In all instances the sealant element 48 should beof a thickness such that in its compressed state the sealant elementwill be maintained in full sealing engagement with face 50 of panel 30in opposition to face 52 of secondary support member 44. In an exemplaryembodiment the spacer plate 54 may also be about 0.08″ thick. It can beseen from FIGS. 4 and 5 that spacer plate 54 has an outer peripheraledge generally co-extensive with the outer margins of panel 30 andsecondary support member 44, while the inner rectangular opening 56 ofspacer plate 54 is spaced outwardly from the edge of secondary supportmember 44 defining aperture 46. The flexible sealant material definingelement 48 should be of composition such that it will remain flexible atthe operating temperature within the confines of bag house 12 and toremain flexible for an extended period of time which typically is thenorm before vent panel 30 is actuated as a result of an explosive eventwithin the bag house 12.

[0040] A flexible, quadrate gasket 58 is adhesively secured to the outerface 60 of secondary support member 44 and has a central rectangularopening 62 of dimensions approximately equal to the dimension ofaperture 46 in secondary support member 44. The gasket 58 is preferablyof synthetic resin tubular foam or other sealing material and in oneembodiment may have a nominal thickness before compression of about0.35″. The outer peripheral margin 64 of gasket 58 is generallycomplemental with the outer perimeter of secondary support member 44.

[0041] The primary support member 26, panel 30, spacer plate 54 andsecondary support member 44 have a series of aligned throughholes 66,each of which receives a respective rivet 68 for rigidly interconnectingthe assembly of primary support member 26, panel 30, spacer plate 54 andsecondary support member 44. The preferred pattern of rivets 68 whichinterconnect primary support member 26, panel 30, spacer plate 54 andsecondary support member 44 is illustrated for example in FIG. 2. Thespacer plate 54 provides a continuous space of uniform distance betweenthe opposing surfaces of spacer plate 54 and panel 30 so that duringfabrication of vent panel assembly 10, predetermined compression of thesealant element 48 will uniformly be obtained.

[0042] The overpressure vent panel assembly 10 also is provided with aplurality of openings 70 therein for receiving fasteners such as bolts72 carried by mounting frame 22 which serve to releasably affix assembly10 to mounting frame 22. Cylindrical spacers 76 (FIG. 4A) surroundingeach of the bolts 72 and of less height that the uncompressed thicknessof gasket 58 assure that the gasket 58 is compressed to a predeterminedextent upon initial installation of the vent panel assembly 10 and tothe same degree of compression each time a replacement vent panelassembly 10 is mounted on support frame 22.

[0043] The primary support member 26 is provided with a series ofspaced, integral lugs 78 which project inwardly a small distance intothe relief opening 28 from respective side segments of member 26. Thelugs 78 are engaged by adjacent surfaces of panel 30 during opening ofthe panel under an overpressure and serve to distribute forces moreevenly across the panel 30 to achieve a sudden and unrestricted openingof the central part of panel 30.

[0044] Exemplary materials of construction for support members 26 and 44and spacer plate 54 include stainless steel such as 304 stainless steel,Inconel, Monel or other exotic alloy depending upon the requirements ofthe particular installation. Panel 30, (as well as the alternateembodiments as described hereunder and illustrated in the drawings) maybe fabricated of varying materials including but are not limited to 304,304L, 316 and 316L stainless steel, aluminum, including aluminum 1100,2024 and 6061, Hastelloy C276, Nickel, Monel and Inconel. The thicknessof panel 30 may typically vary from about 0.005″ to about 0.050″ withthe thickness increasing as the vent area increases and as the burstpressure of the vent increases. A coating may be provided over one sideor both sides of the panel 30 for particular applications againstcorrosion is desired, with Teflon being an example of a suitable coatingagent. The sealant material making up element 48 may be selected from anumber of sealant compositions including Teflon (PFA, FEP, PTFE),silicone, rubbers, elastomers, ceramic materials.

[0045] Quadrate vent panel assemblies of this invention may range fromrectangular shapes of from about 9″×12″ to about 44″×69″.

Operation of One Embodiment of the Invention

[0046] Unitary overpressure vent panel assembly 10 is a rigid,integrated, one-piece structure especially adapted to be supplied as aunit which meets a user's specifications and that may be secured inplace on mounting frame 12 by simply tightening the nuts 74 ofrespective bolts 72. The gasket 58 is compressed against the outer flatface of mounting frame 22 to provide a fluid tight seal. The flexibleelement 48 which is compressed between panel 30 and secondary supportmember 44 also assures that the vent panel assembly 10 is leak proofwhen mounted in operating position on the wall 14 of bag house 12.

[0047] In the event an overpressure condition occurs within the interiorof bag house 12 of sufficient magnitude to effect bursting of panel 30,the central section of the panel within the confines of relief opening28 and aperture 46 gives way along the score lines 38, 40, 42 of scorepattern 34 resulting in full opening of the panel. The trapezoidalsegments of panel 30 on opposite sides of the central score line segment38 fold outwardly in opposite directions while the triangular segmentsof panel 30 defined by V-shaped score line segments 40 and 42 likewisefold outwardly in opposite directions. The trapezoidal and triangularsegments of panel 30 which open fold along the inner edges of reliefopening 28 with the portions of the cover 30 between the extremities ofV-shaped score line segments 40 and 42 functioning as hinges whichpreclude fragmentation of panel 30.

[0048] When full opening of the overpressure vent panel assembly 10occurs as a result of an overpressure condition within the interior ofthe confined area to be protected such as bag house 12, the entire ventpanel assembly 10 may be removed as a unit by simply removing nuts 74whereupon the integrated assembly 10 may be pulled from the wall 14 ofbag house 12 as one piece. Another overpressure vent panel assembly 10of the same construction as the assembly that has just been removed maybe fitted in place, again by simply inserting the replacement assembly10 over bolts 72 followed by retightening the nuts 74.

[0049] The overall rigidity of overpressure vent panel assembly 10 inconjunction with assured internal sealing of the components of theintegrated unit and the complete seal provided by gasket 58 againstmounting frame 22 are important factors not only from the standpoint ofease of mounting and replacement of vent panel assembly 10, but alsobecause of the inherent integrity of the unit and the manner in which itis mounted on the confined area to be protected from an overpressure.

[0050] Although the primary commercial utility for overpressure ventpanel assembly 10 is protecting confined zones from overpressuresresulting from uncontrolled explosions, vent panel assembly 10 may alsoadvantageously be used for protecting an area from an overpressurecondition that is less than an uncontrolled explosion. The conditionthat results in bursting of the vent panel in a protected zone may be anoverpressure ranging from as little as one fourth psi or one half psi toas much as fifteen psi. It is necessary in these low pressureapplications to use materials and closely control the fabrication of thevent panel in order to assure reliable bursting of the panel at aspecified low pressure. In most instances, reliable opening of the ventpanel at low overpressures can be obtained by the depth of the scorepattern as well as the configuration of the score lines. In cases whereit is undesirable to provide score lines in the vent panel for aparticular application, a sharp object such as a knife blade may beprovided in sufficient proximity to a relatively thin vent panel suchthat upon excursion of the panel toward the knife blade or sharp devicewhen an overpressure is applied to the panel on the side thereof awayfrom the knife or device, the blade or other sharp object severs thepanel to effect immediate opening thereof.

Alternate Embodiments of the Invention

[0051]FIG. 6 Embodiment.

[0052] The unitary frameless overpressure vent panel assembly 110 ofFIG. 6 is identical in construction to vent panel assembly 10 exceptthat the panel 130 has a cross-shaped score line pattern 134 comprisingintersecting linear line segments 1, 36 and 138 which extend torespective margins of the relief opening 128 in primary support member126. In this instance, upon occurrence of an overpressure conditionwithin a confined area protected by vent panel assembly 110, the panel20 initially opens at the intersection of score line segments 136 and138 whereupon the quadrate sections defined by line segments 136 and 138fully open outwardly in opposite directions. The unscored areas of panel130 within the confines of relief opening 128 act as hinges so thatthere is no fragmentation of panel 130 as it fully opens.

[0053]FIG. 7 Embodiment

[0054] The overpressure vent panel assembly 210 of FIG. 7 is identicalin construction to vent panel 10, except for the provision of a U-shapedscore pattern 234 in panel 230 which is presented by a central scoreline segment 236 connected to parallel score line segments 238 and 240which are perpendicular to score line segment 236.

[0055] When the panel 230 is subjected to an overpressure adequate toeffect bursting thereof, the central portion of panel 230 fully opensalong score segments 236, 238 and 240 with the portion of cover 230between the outermost ends of score line segments of 238 and 240 remotefrom score line segment 236 functioning as a hinge to preventfragmentation of the panel 230.

[0056]FIG. 8 Embodiment

[0057] The overpressure vent panel assembly 310 of FIG. 8 is alsoidentical to vent panel assembly 10 except for the score pattern 330,which is the presently preferred score pattern. In this instance, aU-shaped score line pattern 334 is located beneath the inner most edgeof primary support panel 326 defining relief opening 328. The score linepattern 334 is defined by a pair of central score lines segments 336 and338 each terminating in a perforation 340 while the side score linesegments 342 and 344 terminate in respective perforations 346. The panel330 fully opens in essentially the same manner when subjected to anoverpressure adequate to effect bursting thereof, as panel 230. Hereagain, the portion of panel 330 between score line segments 336,338,342,344 opens outwardly about a hinge line of panel 330 along the uppermostedge of relief opening 328 of primary support member 326.

[0058]FIG. 9 Embodiment

[0059] The overpressure vent panel assembly 410 of FIG. 9 is of the sameconstruction as vent panel assembly 10 except that the assembly 410 isof circular configuration as depicted and the panel 430 of assembly 410is provided with a cross-shaped score pattern 434 defined byintersecting score line segments 436 and 438 similar to the scorepattern 134 of vent panel assembly 110. Full opening of vent panelassembly 410 takes place in the same manner as vent panel assembly 110.The diameter of the round vent panel assembly may vary typically fromabout 6″ to about 44″.

[0060] Although the vent panel assembly 410 as illustrated has across-shaped score pattern 434, it is to be understood that the panelmay be provided with a variety of score patterns including asemi-circular score pattern in which a portion a portion of the disc isunscored to serve as a hinge upon opening of the disc, and other wellknown patterns as practiced in this art.

[0061]FIG. 10 Embodiment

[0062] The vent panel assembly 510 is of the same construction as ventpanel assembly 10 except for the surface configuration of the vent panel530. In this instance, the portion of vent panel 530 within the area ofthe relief opening (not shown) of primary support member 526 has aseries of undulations defining side by side, parallel, bulged sections532. Score lines segments may be provided if desired in panel 530 alongthe margins of intersection of respective bulge sections 532 with thedeepest score line segment being between domed segments 532′ and 532″.The vent panel 530 having multiple dome sections 532 opens outwardlystarting with the intersection between domed segments 532′ and 532″ andthe opposed portions of the panel 530 then fold outwardly in oppositedirections with the portions of the panel 530 adjacent the side marginsof the relief opening in primary support member 526 functioning ashinges so as to avoid fragmentation of the cover 530.

[0063] Minimum burst pressures for vent panel assemblies 10, 110, 210,310, 410 and 510 range from a minimum of about ¼th psig to about 15 psigwith more typical ranges being from about 2 psig to about 10 psig withthe largest size vents having a minimum burst pressure of no more thanabout 0.5 psig to a maximum burst pressure of about 8-10 psig or higher.The maximum burst pressure is generally the same for all sizes of ventpanel assemblies with the minimum burst pressure decreasing within thespecified range as the size of the vent becomes larger.

[0064]FIG. 14 Embodiment

[0065] Viewing FIG. 14, a customer's vessel 80 has a cylindrical processflange 82 integral with vessel 80 and aligned with the opening 84 in theside wall of vessel 80. A circular unitary overpressure vent panelassembly 610 is clamped between flanges 82 and 86 and has an annularprimary support member 626, a annular secondary support member 644, acircular vent panel 630 and an annular spacer plate 654 between panel630 and spacer plate 654. An annular tubular, flexible element 648 isclamped between panel 630 and secondary support member 644. Annulargasket 658 is interposed between the secondary support member 644 andthe opposed face of flange 82. A series of bolts 672 served to clamp thevent panel assembly between flanges 82 and 86.

[0066] The vent panel assembly 610 operates in the same manner as ventpanel assembly 10 as described above.

[0067] Embodiment of FIGS. 15, 16 and 17

[0068] The overpressure vent panel assembly 710 illustrated in FIGS. 15and 16 is especially adapted for vacuum applications and is shown asbeing clamped between the flange 88 of a customer's vessel or structureand an opposed flange 90. The primary support member 726 differs fromthe support member 26 principally in the provision of an upstandingquadrate flange 726 a projecting away from the main body of supportmember 26 in a direction opposite the peripheral out-turned lip 729 ofsupport member 26.

[0069] The vent panel 730 which for example may be of the multiple domeconstruction of panel 530 in the FIG. 10 embodiment has a plurality ofout-turned tabs 730 a (FIGS. 16 and 17) which overlie and complementallyengage the inner surface of flange 726 a. A tubular flexible sealantelement 748 of cross sectional shape as shown in FIG. 13 is interposedbetween the inner surface of vent panel 730 and the secondary supportmember 744 of vent panel assembly 710. The extent of compression offlexible sealant element 748 is controlled by the quadrate spacer plate754 having a rectangular central opening 756.

[0070] A FIG. 8 shaped rupture strip 790 (FIG. 17) is interposed betweeneach tab 730 a and a proximal portion of the flange 726 a of primarysupport member 726. Openings 792 and 794 are provided in opposite endsof each strip 790 between the reduced width mid-section 790 a thereof. Arivet 796 carried by each tab 730 a extends through the opening 792 of arespective strip 790 while another rivet 796 extending through opening794 of each strip 790 and secured to flange 726 a is received within aclearance slot 798 in each tab 730 a.

[0071] The vent panel assembly 710 is especially adapted for use inprotecting confined areas where a vacuum exists. In view of the factthat the outer most edge portion 730 b of panel 730 rests on the inneredge of spacer plate 754, the multiple dome panel 730 resists collapseunder the vacuum within the protected zone. The provision of a multipledomed vent panel provides improved resistance to reverse buckling ofpanel 730, even during cycling of the level of vacuum in the protectedarea.

[0072] In the event of an overpressure within the protected zone, and ifthat overpressure is sufficient to cause the restricted cross-sectionalareas of strips 790 to sever, the panel 730 is released for immediatedisplacement from support between primary support member 26 andsecondary support member 744.

[0073] As previously explained, the vent panel 730 has a hinge sectionon one of the long sides thereof to prevent fragmenting of the ventpanel and allowing the pressure that is built up within the protectedzone to escape through the opening provided by vent panel assembly 710.

We claim:
 1. A unitary overpressure vent panel assembly for installationover and removal as a unit from a pressure relief area of a confinedzone to be protected from the buildup of overpressures, said unitaryvent panel assembly comprising: a rigid, generally planar primarysupport member having a central pressure relief opening; a frangiblevent panel carried by the primary support member in full closingrelationship to the relief opening; a rigid, generally planar secondarysupport member overlying the vent panel and having a central reliefaperture; and structure interconnecting the primary support member, thevent panel and the secondary support member in generally circumscribingrelationship to the portion of the vent panel aligned with the pressurerelief opening and central relief aperture respectively to provide arigid, integrated, one-piece overpressure vent assembly.
 2. A unitaryoverpressure vent panel assembly as set forth in claim 1 wherein saidvent panel is provided with at least one line of weakness defining aburst pattern of the panel when subjected to an overpressure ofpredetermined magnitude;
 3. A unitary overpressure vent panel assemblyas set forth in claim 1 wherein said central relief aperture issubstantially co-extensive in dimensions with the relief opening in theprimary support member;
 4. A unitary overpressure vent panel assembly asset forth in claim 1 wherein said primary support member has a mainplanar body and is provided with a lip substantially around theperimeter thereof and projecting away from the main body of the primarysupport member for increasing the rigidity of the primary supportmember.
 5. A unitary overpressure vent panel assembly as set forth inclaim 1 wherein said structure includes a plurality of mechanicalfasteners extending through the primary support member, the vent paneland the secondary support member.
 6. A unitary overpressure vent panelassembly as set forth in claim 3 wherein said mechanical fasteners eachcomprise a rivet.
 7. A unitary overpressure vent panel assembly as setforth in claim 1 wherein said structure comprises a weld line connectinga portion of the panel outside of and in generally circumscribingrelationship to the relief opening and the aperture, to at least one ofthe support members.
 8. A unitary overpressure vent panel assembly asset forth in claim 1 wherein said structure comprises a line of adhesiveconnecting a portion of the panel outside of and in generallycircumscribing relationship to the relief opening and the aperture, toat least one of the support members.
 9. A unitary overpressure ventpanel assembly as set forth in claim 1 wherein is provided a flexible,generally planar gasket joined to and overlying the face of thesecondary support member remote from the vent panel, said gasket beingprovided with an opening at least substantially co-extensive in areawith the relief opening of the primary support member and the apertureof the secondary support member respectively.
 10. A unitary overpressurevent panel assembly as set forth in claim 1 wherein is provided asealant element between the panel and at least one of the supportmembers in surrounding relationship to the relief opening in the primarysupport member and the aperture in the secondary support member.
 11. Aunitary overpressure vent panel assembly as set forth in claim 10wherein said sealant element is a tubular, flexible sealant materialtrapping a quantity of a compressible fluid.
 12. A unitary overpressurevent panel assembly as set forth in claim 1 wherein is provided anintermediate support member between the vent panel and the secondarysupport member, said intermediate support member having an openingtherein substantially co-extensive in dimensions with the relief openingin the primary support member and the central aperture in the secondarysupport member.
 13. A unitary overpressure vent panel assembly as setforth in claim 1 wherein said support members and the vent panel are ofgenerally quadrate, complemental configuration.
 14. A unitaryoverpressure vent panel assembly as set forth in claim 1 wherein saidsupport members and the vent panel are of generally circular,complemental configuration.
 15. A unitary overpressure vent panelassembly as set forth in claim 1 wherein said line of weakness isconfigured to define at least one panel hinge portion upon bursting ofthe panel by said overpressure to prevent fragmentation of the panelupon opening thereof.
 16. A unitary overpressure vent panel assembly asset forth in claim 1 wherein said support members of the frame assemblyare provided with bolt through holes for fastening of the frame assemblyin place over said pressure relief area of the confined zone.
 17. Aunitary overpressure vent panel assembly as set forth in claim 1 whereinthe portion of said vent panel aligned with the pressure relief openingof the primary support member and the aperture of the secondary supportmember is provided with a series of undulations therein.
 18. A unitaryoverpressure vent panel assembly as set forth in claim 17 wherein saidsupport members are of generally quadrate configuration and saidundulations define a plurality of side-by-side generally parallel,concavo-convex domed sections.
 19. A unitary overpressure vent panelassembly as set forth in claim 18 wherein the concave surfaces of thepanel are on one side of the panel and the convex surfaces of the panelare on the opposite side thereof.
 20. A unitary overpressure vent panelassembly as set forth in claim 1 wherein in provided at least one sharpobject in sufficiently close relationship to the vent panel to effectsevering upon excursion of the vent panel toward the object as a resultof a predetermined overpressure being applied to the side of the ventpanel opposed to said object.